1. Field of the Invention
The invention relates to a light source device, and especially to a light source device which is used for a projector device.
2. Description of Related Art
In a projector device of the projection type, there is a demand for uniform illumination of images with sufficient color reproduction on a rectangular screen. Therefore, as the light source, a discharge lamp of the short arc type, like a mercury lamp, a metal halide lamp or the like, is integrated into the reflector and used. The reflector has an essentially concave overall shape and consists of a concave reflection part and a cylindrical neck region.
FIG. 7 schematically shows the arrangement of such a light source device which consists of a discharge lamp L and a reflector R. The fixing of the discharge lamp L and of the reflector R takes place such that the vicinity of a base B which is attached to one end of the discharge lamp is filled with an adhesive. The arc radiance spot P of the discharge lamp L must furthermore be positioned at a first focal point of the reflector R. This is because the radiant light of the discharge lamp L can be used with high efficiency when the arc radiance spot P is at the first focal point of the reflector R.
Therefore, the following sequence is undertaken to produce the light source device.
First, before filling with adhesive, the discharge lamp L is moved with simultaneous operation of the discharge lamp L such that the arc radiance spot P is located at the first focal point of the reflector R. Thus, the positional relationship to the reflector R is adjusted.
Next, filling with adhesive is performed after the arc radiance spot P has been brought into agreement with the first focal point of the reflector R. Thus, the discharge lamp L and the reflector R are attached to one another. The two can also be directly attached to one another; although; in the drawings, the discharge lamp L and the reflector R are attached via a holding component H.
This technique is described, for example, in Japanese patent application publications JP-A-2003-29338 and JP-A-2000-105425.
However, in the above described production sequence, there were the following disadvantages:
(1) For positioning of the discharge lamp relative to the reflector, devices and apparatus like a current source for operating the lamp, an optical system for illuminating the arc radiance spot, a device for measuring the illuminance, a screen and the like were necessary.
(2) In the case of using devices for measuring the illuminance, such as an optical template of an illumination meter and the like over a long time, measures against heat and correction of deterioration were necessary.
(3) Even if the discharge lamp is operated for positioning, it is necessary to wait until the radiation intensity has stabilized. Even after positioning, the discharge lamp was turned off, it was necessary to wait until it cooled off, and afterwards, the adhesive was injected. Therefore, time had to be spent for fixing of the discharge lamp and the reflector to one another.
Furthermore, since there is a demand for a very large amount of light in current projector devices, there is also a demand for very high accuracy in the positioning of the discharge lamp and the reflector relative to one another. This is because the attainable amount of light decreases greatly when the arc radiance spot of the discharge lamp and the focal point of the reflector deviate from one another.
On the other hand, the price of projector devices drops more and more from year to year. Accordingly, the price of the light source device also drops continuously. Therefore, it is desirable to be able to produce both with low costs and also to obtain a sufficient amount of light.